Shuttered oven-door window

ABSTRACT

A door for a self-cleaning oven is provided with a window which is closed when the door is locked for self-cleaning of the oven, thereby preventing heat losses through the window during selfcleaning. The window closing means comprises a series of rotatable flat plates, movable from a mutually parallel disposition, in which the window is open, to a disposition in which they are all disposed in the same plane parallel to that of the window, thereby obstructing the window, operable in response to movement of the door locking mechanism.

United States Patent [541 ""SH'TTRED ovEN-oon'wmnow 3 Claims, 5 DrawingFigs.

PATENTEU fines Isn 3Q 555; 054

snm 1 or 2 INVENTOR. DAVID GIBBONS SMITH HELMUT L DWIG HAGENBUCH.

ATTORN EYS PATENTED m3231971 SHEET 2 UF 2 ONS SMITH ZNBUCH.

ATTORNEYS ,.N., W W B B @W DW Mm DL E H SHUTTERED OVEN-DOOR WINDOW theoven door as was previously required.

More recently, the cook stove manufacturing industry has developedvarious forms of an oven which may be heated to a relatively hightemperature for the purpose of cleaning food soil from the interior ovenwalls b y pyrolysis. The temperatures which are involved in thepyrolitic cleaning action are substantially higher than those which areencountered in normal cooking operations. Normal cooking temperatures donot, as a rule, exceed 500 F. to 550 F. whereas the pyrolitic cleaningaction takes place somewhere between 800 F. and l,000 F.

Initially, it was believed that it would be necessary to sacritice thepresence of a window in the oven door in order to achieve the obviousadvantages of the self-cleaning feature and the attendant hightemperatures. The reason for this is that the conventional double-panewindow design of theprior art is not capable of yconfining the increasedamount of heat energy to the oven cavity and, accordingly, the heat lossthrough the window was excessive and radiation through the windowpresented a hazard to the housewife.

The present invention, however, makes is possible to retain theadvantages of a window in the oven door while, at the same time,providing simple and automatic means whereby, during the hightemperature self-cleaning cycle, the window may be obstructed so as toretain the high temperature within the oven and to prevent bothexcessive heat loss and radiation through the window.

According to the present invention, in one embodiment, an oven doorwindow is provided with a peripheral frame within which are mounted aplurality of spaced, parallel, substantially flat blades, rotatableabout their longitudinal axes from a first position in which the flatblades are parallelto one another and normal to the plane containing thewindow so that the interior of the oven may be viewed between theblades, to a second position wherein the blades are rotated throughsubstantially 90 so as to lie in substantially a single plane parallelto the plane of the window whereby the window is completely obstructedand closed by the blades, operating means being provided tosimultaneously move all of the blades as a result of a door lockingfunction which is a precedent to the initiation to the self-cleaningcycle.

A preferred embodiment of the invention will now be disclosed in detailwith reference to the accompanying drawings in which like parts aredenoted by like reference numerals in the various views and in which:

FIG. 1 is a perspective view, partly cut away and exploded in order toshow an oven door embodying a shutteredwindow constructed and arrangedin accordance with the present invention;

FIG. 2 is a section view taken along line 2-2 ofan assembled door asillustrated in FIG. 1;

FIG. 3 is a fragmentary detailed view of a portion of the shutteractuating mechanism illustrated in FIG. l;

FIG. 4 is a fragmentary detailed view showing the components of FIG. 3assembled and in a different position; and

FIG. 5 is a fragmentary view showing a portion of the shutter actuatingelement.

Turning now to FIGS. l and 2, an oven door embodying the shutteredwindow of the present invention is illustrated. In FIG. l, the door maybe seen to comprise an inner shell l0 having flanged edges which willengage with an outer shell 1l. Conveniently, the outer shell ll isprovided with flanged edges, the lower such edge being provided withtabs l2 which may be inserted in slots 13 in the corresponding edge ofthe inner shell l0 to secure the two shells together along the loweredge. The upperedges may then be secured together by means of screwssuch as 14 received in corner brackets I5 carried by the upper cornersofthe outer shell l1 of the door.

As seen in FIG. 2, the inner shell 10 is also provided with a rearwardlyextending sheet metal plug or boxlike portion I6 which is of a size suchthat it will fit relatively snugly within the opening to the oven. Theoven opening is indicated in dotted lines in FIG. 2 by the oven upperwall 17 and the oven bottom wall 18.

The plug or boxlike member 16 is secured to the rearward face of theinner shell l0 by brackets 16a and is provided with a heat resistant,compressible seal member 19 so that the oven door, when in its closedposition, will tightly close the oven opening with the boxlike section16 extending slightly into the oven cavity.

The rear face of the plug 16 is provided with an aperture defined by aperipheral flange 20, the flange 20 receiving a sheet of heat resistantglass 21 such as that sold under the trade mark Pyrex t The outer shell1l of the door is also provided with an opening defined by an inwardlyextending peripheral flange 22, this f'iange engaging the rim 23 of aframe 24 which mounts a pair of spaced, parallel panes of glass in aself-contained unit which is of conventional construction. l

The plug or boxlike section, interiorly of the glass pane 2l presents arecess aligned with the three panes of glass constituting the window inthe door within which the shutter mechanism is mounted.

In FIG. l, the shutter mechanism will be seen to comprise achannel-section frame 25 which defines a rectangular openingsubstantially coextensive with the size of the panes of glass`constituting the window. The frame 25'comprises side members 26 and 27and a bottom member 28 and a top member 29. The frame is secured inposition by means of brackets 30 which may be spot welded to the innersurface of the plug or boxlike member 16. Angular brackets 31 are thensecured to the brackets 30 by means of screws so that one free end maybear upon one flange of the channel-section frame member and retain itin position. As seen in FIG. 2, the frame members (only 28 and 29 ofwhich are shown) serve also to retain the pane of glass 21 within theflange 20.

Bottom and top frame members 28 and 29 are provided with a plurality ofspaced and aligned apertures 32 by means of which the spaced, parallel,substantially flat blades 33 may be mounted as shown in FIG. l. Theblades are capable of rotating through from a first position as shown inFIG. l, in which they are parallel to one another and normal to thepanes of glass so that a housewife may see through the window to aposition in which the flat blades 33 are substantially coplanar andparallel to the panes of glass as shown, in a fragmentary view, in FIG.3.

Turning now to FIGS. 3 and 4, each of the bladesis formed from a lengthof extrusion, conveniently of aluminum, defined by a central rib portion34 from which extends, on both sides. the blade portion 35 and 36. Oneof the blade portions 36 is provided with an offset segment 37 along itsedge so that, as seen in FIG. 3, the end of blade portion 35 may liewithin the offset portion 37 of an adjacent blade, thereby enabling theblade portions of adjacent blades to be coplanar when they are in theposition shown in FIG. 3.

At the lower end of the blades (not shown in detail), each blade isprovided with apin inserted in a central bore 38 in the central rib 34and such pin is then inserted through the aperture 32 in the bottomframe member 28. A'pin 39 ofthe kind just described may be seen in FIG.2.

Each of the blades 33 is provided, at its upper end, with a cranked pin40 having a lower portion 41 adapted -to be inserted in the bore 38.Small tabs 42 may be struck from the material of the pin 40 and thesetabs may be received in slots 43 in the bore 38 so as to fix the crankedpin 40 relative to the blade 33 to resist rotation relative thereto. Theupper portion ofthe cranked pin 40 is offset as at 44.

The blades 33 are pivotally mounted in the upper frame member 29 bypassing through apertures 45 provided therein aligned with apertures 32in bottom frame member 28.

The oft'set portions 44 of the cranked pin 40 are then received in aplurality of apertures 46 in a slidable plate 47 lying above framemember 29 and linking the offset portions 44 of all of the cranked pins40 associated with each of the blades 33.

From the construction so far described, it will be apparent that thesliding plate 47 may be reciprocated to move the blades, in unison, fromthe position shown in FIG. 3 to the position shown in FIG. 4 and viceversa.

The movement of the sliding plate 47 is achieved by a mechanismdisclosed in FIG. 1.

First, the sliding plate 47 is supported in slotted tabs 48 carried bythe upper frame member 29 and, centrally of its length, is provided withan operating arm or extension 49.

Secured to the inner door shell is a mounting bracket 50 upon which ispivotally carried a downwardly extending lever 51 to which is welded, at52, a spring steel element 53 which extends upwardly to position ahorizontally disposed portion 54 immediately inside and below anelongated horizontal slot 55 formed in the inner door shell l0.

The oven construction with which the door is associated is provided witha door locking element comprising a rod 56 having a formation of ahooked end S7 which projects through the portion 58 of the stoveconstruction and which is positioned so that it will enter the elongatedhorizontal slot 55 when the door is in the closed position. As long asthe hooked portion 57 is in the horizontal position shown in FIG. l, thedoor may be freely opened and closed without interference.

However, when the high temperature, self-cleaning, pyrolitic cycle isinitiated, the shaft 56 is rotated through substantially 90 in thedirection of the arrow 59 with the door in the closed position. Thehooked portion 57, during this rotation, will encounter the horizontalportion 54 of the element 53 which will be pressed downwardly, therebycausing the lever 51 to pivot to the right about pin 60 as seen in FIG.1.

Turning now to FIG. 5, lever 51 may be seen to be provided with aforwardly projecting tab 61 at its lower end, provided with an aperture62 within which is received the hooked end 63 of the stiff wire 64. Thestiff wire 64 engages operating arm 49 of the sliding plate 47. The arm49 is provided with an upwardly bent portion 65 at its free end and thisportion 65 is slotted at 66, the slot passing entirely through theelement 65 and a short distance into the horizontal extent of the arm49. The stiff wire 64 is provided with a suitably located crook at 67which engages the slot 66 and, thereby, is firmly secured to the arm 49.The end 68 of the wire 64 is either formed into or secured to a tensionspring 69, the free end of which is mounted to a bracket 70 carried bythe inner door shell l0.

The spring 69 will constantly urge the arm 49 and` therefore, thesliding plate 47 to the left, as seen in FIG. l and will urge,therefore, the shutters or blades 33 to the "open" position as shown inFIG. l. This position is determined by a stop constituted by a tab 71struck up from the material of the sliding plate 47 which engages theslotted bracket 48 within which the sliding plate 47 is received.

When the door is closed and shaft 56 is rotated through substantially tolock the door, the hooked end 57 of the door locking element will, inaddition to engaging the interior surface of the inner door shell 10 tothereby lock it in the closed position, also depress the horizontalelement S4, swing the lever 51 to the right as seen in FIG. l, slide thesliding plate 47 to the right as seen in FIG. l and move the blades 33from the position shown in FIG. 4 to the position shown in FIG. 3,thereby effectively shuttering the oven door window in a manner whichwill make it possible for the windowed door to retain the hightemperatures within the oven for the self-cleaning cycle and to reducethe heat loss and radiation through the window to an acceptable level.

We claim: 1. An oven door having a window and obstruction means for thewindow, the obstruction means comprising a peripheral rectangular frame,a plurality of spaced, parallel, substantially flat blades mountedwithin the frame for rotation about their longitudinal axes between afirst, open position in which the blades lie in parallel planes, eachnormal to the plane of the window and a second, closed position in whichthe blades lie substantially in a single plane parallel to the plane ofthe window, the means mounting the blades for rotation within the framecomprising, at one end of each blade, a pin extending axially of theblade through one side of the frame and then extending transverselythereof to a pivotal attachment with an operating plate extending thelength of the said one side of the frame and linking all the said pinstogether to rotate in unison, rotatable means for locking the door inits closed position having a formation which will pass through aregistering slot in the door in an unlocked angular position of theelement but which will not pass through the slot in a locked angularposition of the element, cam means within the oven door adjacent theslot and engaged by the door locking element when in its locked angularposition, said cam means being mounted for rotation on the doorstructure, an arm extending from the cam means and connected to theoperating plate, rotation of the cam means being converted thereby toreciprocation of the operating plate to move, in unison, the blades fromtheir first open position to their second closed position, upon rotationof the door locking element to its locked angular position within thedoor.

2. An oven door as claimed in claim l wherein means are provided to biasthe blades to their first open position.

3. An oven door as claimed in claim 2 wherein the means to bias theblades to their first open position comprises a tension coil springextending between one end of the operating plate and standing structureon the oven door.

1. An oven door having a window and obstruction means for the window,the obstruction means comprising a peripheral rectangular frame, aplurality of spaced, parallel, substantially flat blades mounted withinthe frame for rotation about their longitudinal axes between a first,open position in which the blades lie in parallel planes, each normal tothe plane of the window and a second, closed position in which theblades lie substantially in a single plane parallel to the plane of thewindow, the means mounting the blades for rotation within the framecomprising, at one end of each blade, a pin extending axially of theblade through one side of the frame and then extending transverselythereof to a pivotal attachment with an operating plate extending thelength of the said one side of the frame and linking all the said pinstogether to rotate in unison, rotatable means for locking the door inits closed position having a formation which will pass through aregistering slot in the door in an unlocked angular position of theelement but which will not pass through the slot in a locked angularposition of the element, cam means within the oven door adjacent theslot and engaged by the door locking element when in its locked angularposition, said cam means being mounted for rotation on the doorstructure, an arm extending from the cam means and connected to theoperating plate, rotation of the cam means being converted thereby toreciprocation of the operating plate to move, in unison, the blades fromtheir first open position to their second closed position, upon rotationof the door locking element to its locked angular position within thedoor.
 2. An oven door as claimed in claim 1 wherein means are providedto bias the blades to their first open position.
 3. An oven door asclaimed in claim 2 wherein the means to bias the blades to their firstopen position comprises a tension coil spring extending between one endof the operating plate and standing structure on the oven door.